Recently, a smart parking assist system (SPAS) for supporting reverse parallel parking, perpendicular parking, and the like has been developed.
The SPAS may include a plurality of ultrasonic sensors, an electronic stability controller (ESC), a motor driven power steering system (MDPS), an SPAS electronic control unit (ECU), a human machine interface (HMI), and the like as illustrated in FIG. 1A.
In general, a plurality of ultrasonic sensors mounted in a vehicle includes 8 (8EA) front and rear ultrasonic sensors and four (4EA) lateral ultrasonic sensors, and the front and rear ultrasonic sensors detect obstacles in a longitudinal direction based on a travelling direction of a vehicle, and the lateral ultrasonic sensors detect obstacles in a transverse direction. The information about the detected obstacle is transmitted to the SPAS ECU.
As illustrated in FIG. 1B, the SPAS ECU detects a position of the obstacle and a parking space based on the information about the detected obstacle (S12). The SPAS ECU detects a parking trace for parking the vehicle in the detected parking space, and transmits a steering command corresponding to the detected parking trace to a steering device (S14).
The SPAS ECU controls steering of the vehicle according to the steering command by using the steering device (S16), and then completes assistance of smart parking of the vehicle by aligning a posture of the vehicle (S18).
As described above, the SPAS performs various processes, and process S12 of detecting the parking space, which is first performed among the various processes, is a very important process considerably influencing the parking trace generation and the parking completion performance of the vehicle.
Accordingly, in the process of detecting the parking space, the parking space and the obstacle need to be accurately recognized, but the ultrasonic sensor used in the SPAS in the related art has a limit to the performance of accurately recognizing a parking space and an object, other than the measurement of a distance to the obstacle.
Nevertheless, it is difficult to replace the ultrasonic sensor with another sensor in the SPAS of the related art in respect to a cost aspect.